1. Field of the Invention
This invention relates to an image receiver material, such as a sheet for heat transfer recording having a dye receiver layer receiving a dye transferred from the heat transfer sheet on melting or sublimation by heat, a sheet for ink jet recording having an ink receiver layer for receiving an ink jet ink, or a sheet for recording received toner. More particularly, this invention relates to a seal type image receiver material subjected to half-cut processing and specifically to a leaf or roll type image receiver material in which, even when the material is wound about a transport roll of a smaller diameter, the image receiver sheet is not peeled off such as to evade running troubles in the printer.
This application claims priority of Japanese Patent Application No. 2002-205142, filed on Jul. 15, 2002 and Japanese Patent Application No. 2003-076524, filed on Mar. 19, 2003, the entireties of which are incorporated by reference herein.
2. Description of Related Art
Recently, a thermal print system, in particular a thermal dye transfer print system which permits an extremely clear full-color image, is attracting attention. In the thermal dye transfer print system, a dye layer of the thermal transfer recording sheet is superposed on a dye receiver layer of a sheet for thermal transfer recording (printing sheet) containing a dye affixing type resin, and the superposed area is heated by e.g. a thermal head depending on a desired image to transcribe the dye of the dye layer to the dye receiver layer to form an image. Recently, a seal type sheet for thermal transfer recording, provided with an adhesive layer, is marketed in order to permit the sheet for thermal transfer recording from the transfer recording step to be freely affixed to various objects.
Such seal type sheet for thermal transfer recording includes a separator having a release agent layer on a release sheet base material, and an image receiver sheet, having an adhesive layer on one surface and a dye receiver layer on the other surface of the receiver sheet base material. The separator and the image receiver sheet are layered together so that the release agent layer and the adhesive layer face each other and so that the separator and the image receiver sheet may be peeled off at the release agent layer and the adhesive layer. In use, the image receiver sheet, carrying the image, is peeled off from the separator and affixed to various objects.
Such seal type sheet for thermal transfer recording is required to satisfy the following requirements: 1) high image recording concentration; 2) smooth transfer recording; and 3) facilitated accurate peeling of the image receiver sheet from the separator after recording the image by transfer recording. It should be noted that, as for peeling, it is known from Japanese Laying-Open Patent Publication 64-82988, page 1, FIGS. 1 and 2 to perform half-cut processing on the image receiver sheet or on the separator in order to permit facilitated peeling of an area carrying the transcribed image.
An adhesive label sheet of a simplified structure, in which plural labels, each having an adhesive layer, are provisionally bonded from the side adhesive layer to the release sheet, is also known and has been used for a long time. One of the manufacturing methods for the adhesive label sheets is such a method in which an adhesive sheet is provisionally bonded to the entire surface of the release sheet, and a label area only is die-cut, so as not to cut the release sheet, to provide a half-cut to remove an unneeded portion. In the case of this manufacturing method, it is proposed in Japanese Laying-Open Patent Publication 50-155220, pages 1 to 3, to provide a half-cut line, in other than the portion of the adhesive sheet in register with the label, in order to prevent the label from being partially peeled off when removing the unneeded portion and in order to prevent the entire label from being peeled off along with the unneeded portion.
However, with the conventional half-cut processing, such as is disclosed in the Japanese Laying-Open Patent Publication 64-82988, difficulties are encountered in achieving “smooth transfer recording in a small-sized printer featured by high speed printing” and “facilitated peel-off of the image receiver sheet, carrying the image after transfer recording, from the separator” in combination. Specifically, in order to provide for facilitated peeling of the image receiver sheet, carrying the sheet, from the separator, the half-cut is deepened, the adhesive layer is lowered in its bonding strength level or the release agent layer is improved in releasing properties. However, if, when the image receiver material is wound about a transport roll of a smaller diameter in the printer at the time of feeding/ejecting the paper sheet before and after transfer recording, the image receiver sheet of the sheet for thermal transfer recording is high in toughness, the image carrying area tends to be peeled off from the half-cut area (half-cut peel-off) to render it impossible to prepare a desired image. In the worst case, running troubles, for example, paper is chocked, are produced. Thus, in order to make the half-cut less liable to be peeled off even in case the sheet for thermal transfer recording is wound on the roll of a smaller diameter, attempts are being made to make the half-cut shallower, to increase the bonding strength of the adhesive layer or to degrade the releasing properties of the release agent layer. However, in these cases, there persists the possibility that, after thermal transfer recording, the image receiver sheet, now carrying an image, can hardly be released from the separator. Although it is contemplated to lower the tenacity of the image receiver sheet, the sheet for thermal transfer recording tends to lose its tenacity, thus lowering the image quality. Additionally, there is also a possibility that the sheet for thermal transfer recording becomes unable to withstand the pressure applied from the thermal head and is thereby warped to produce running troubles.
On the other hand, in a manufacturing method for an adhesive label, disclosed in Japanese Laying-Open Patent Publication 50-155200, the peel-off of the adhesive label only is at issue, while the loading of the adhesive label on the thermal transfer recording printer, an ink jet printer or a laser printer to form an image is not presupposed. The problem of half-cut peel-off in the course of the image formation is not recognized whatsoever in this publication. Consequently, no measures have been contemplated for providing a certain type of a half-cut line in a necessary portion other than the label equivalent portion of the adhesive sheet for possibly avoiding the problem of half-cut peel-off in the sheet for thermal transfer recording in the printer.
This problem equally occurs in other types of the seal type image receiver material, for example, a sheet for ink jet recording or a toner receiver recording sheet.